Some hints on using the SWD interface to program devices

[rolfmyhre]

I am soon going crazy! I have used 4 different types of USB -> SWD (Cortex M-10 adapter) programmers like STLINK/V2, Segger J-Link etc. I have made PC boards with several different STM32 MCU types, and what happens is that on some boards the Flash programming goes OK, but in most cases I get some error messages like "DEV NO DEV", "Failed to download application", "Missing device ID code" etc. I have tried to fiddle with general settings like speed and other interface things, but if the card first refuses to be programmed there seems to be no cure - except once when speed adjust worked. CAN ANYONE HELP? Rolf

[Tesla DeLorean]

Perhaps start by looking at board design issues.

Power and reset are primary issues. The JTAG/SWD are usually pretty robust.

[S.Ma]

grab a scope, monitor the supply lines if there is an external oscillator check on it, and finally look at the SWD lines, RST AND BOOT0 pin level. I think STLink needs MCU Vdd to checkout its GPIO voltage level too.